At present, domestic and foreign related polylactic acid production and processing of patents in more than thousands of. According to Griman and so on the domestic and foreign domain patent analysis of polylactic acid, March 2005 ago, its use of polylactic acid for the keyword, in China's patent database for the search, found that with polylactic acid preparation, application and other related patents a total of 154, of which the domestic applicant open 96, in turn, medical, preparation, packaging and fiber, For 56, 26, 6 and 4 respectively, 58 articles published by foreign applicants. In the Derwent Patent Database, "ts= (Polylacticacid or Polylactide) NOTPN=CN" as a strategy to retrieve nearly 1740 foreign patents, including 542 medical patents, 517 patents for the preparation, Packaging patents 293, fiber patents 419. According to the statistic analysis of the patent family of foreign Derwent, it is found that the main applications of PLA patents are Japan, USA, Germany, France and UK. In the Derwent Patent database, the application of polylactic acid in packaging 293 articles, 419 related patents, including the largest number of countries in Japan, the United States and Germany. China's patent database, the domestic poly-lactic acid patent applications mainly in universities, which apply for polylactic acid-related patents in colleges and universities are: Zhejiang University, Tianjin University, Wuhan University, East China University of Technology, Tsinghua University, Nankai College, Southeast University, Shanghai Jiaotong University, Chongqing University, Jinan University, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, etc. enterprises also have a certain amount of application, but in contrast, the company's poly-lactic acid patent applications far less than the university.
From Der Double nr Patent database can be found that poly-lactic acid patent for the majority of foreign applicants for enterprises, and many for the international well-known large enterprises. BRUSSELS Biotech (BE) February 13, 2004 open World Patent WO 2004 014889, reported the preparation of polylactic acid, Its independent rights include the following: ⑴: (a) the preparation of lactic acid or lactic acid derivative solution to prepare the molecular weight of 400-2000, total lactic acid equivalent acidity 119-124.5%, optical purity equivalent to 90-100%l-polylactic acid of the low polymer (b) A low polymer and a poly catalyst were added to the polymerization reactor to prepare a liquid phase containing lactic acid and a high polymer-rich gas phase; (c) The condensed gas phase is obtained by liquid crude lactic acid, (d) The crude lactic acid is extracted by crystallization; (e) separation and discharge of crystals to obtain a wet cake rich in lactic acid crystals; (f) Drying of wet cakes to obtain pre-purified lactic acid
and (g) the purified lactic acid obtained by crystallization and purification of lactic acid was lower than that of 10meq/kg, water content below 200ppm and meso-lactate content was less than 1%, and polylactic acid was prepared by ⑵ polymerization. Botelho T etc 2004 years public patent WO-057008-A1, a method of preparing polylactic acid for confectionery packaging materials is reported, which is mainly obtained by fermentation method, and its embodiments are as follows: The Culture Solution (451) (including whey, Milk proteins and other nutrients, such as inorganic salts and ℃, are heated to 70 and remain for 45 minutes, and then cooled to 45 ℃. Add Lactic Acid Bacteria Helveticus (9 grams) and Flavourzyme (RTM) (A) (26.5 grams). Batch fermentation for 9 hours, supplement with whey, lactose and Flavourzyme (RTM) of fresh broth. Using ammonia to regulate ph 5.75, biological density control in 7-8%, fermentation process of continuous ventilation, ventilation volume of 1 liters/minute. During the 34-day fermentation period, the dilution rate was 0.15-0.3/hours. The lactate in the effluent is 4%, the dilution rate is 0.3/h and the yield is 12 g/L. Hour.
The lactic acid outflow liquid was separated by ion exchange resin and chelating agent, and the recovery rate was 85-90% after two times of continuous electrodialysis. Hanzsch Bernd and other August 21, 2003 public U.S. Patent US 2003 158360, reported a method of preparation of polylactic acid, the steps are as follows: fermented starch produce lactic acid, through ultrafiltration, nano filtration and/or electrodialysis Ultra purified lactic acid, concentrated lactic acid, preparation of Prepolymer,
The ring was dissolved and poly-lactic acid was purified, the double lactic acid, the open loop double lactic acid polymer and the monomer poly-lactic acid were obtained. Shimadzu Corp. October 15, 2002, the public JP 2002 300898, reported a production of lactic acid and polylactic acid method.
The method is as follows: ⑴ use of ammonium lactate to synthesize lactate; ⑵ In addition to Dibutyltin catalyst, polycondensation lactate ester, synthesis microsegregation is less than 15000mol.wt polylactic acid (polylactic acid), ⑶ polylactic acid to obtain lactic acid; This method further includes the preparation of polylactic acid by open loop lactic acid polymers. Shimadzu Corp., Ohara H, TOYOTA Jidosha KK, ITO m and Sawa's patent of August 8, 2002, and 2002, reported on the preparation of lactic and polylactic acid for the production of biodegradable plastics, one of the embodiments of the patent The methods reported are as follows: the fermentation of ammonium L-lactic acid under 90-100 ℃ with ethanol, separation and collection of ethanol, 120 ℃ under the reaction of water, ethyl lactate purified by distillation, in Dioctyl presence in 160 ℃ polycondensation of ethyl lactate, and the removal of ethanol. The obtained reaction solution was distilled under 200 ℃ to obtain lactic acid, and the yield was 99.2%. Lactic acid was made by polymerization of lactic acid in the presence of dioctyl. NATL Inst of ADVANCED INDUSTRIAL Science TECHNOLOGY METI, Konan Kako KK and Tokiwa YUTAKA2001 year August 21, the public Japanese patent JP 2001 224392, reported the mining Polylactic acid was prepared by using hydrolysis enzyme instead of organic metal catalyst.